How to Prepare the Power Supply and Connect to the Electronics on Your RepRap 3D Printer

By Kalani Kirk Hausman, Richard Horne

When you are ready, you will need to prepare and connect your 3D printer’s power supply. Check to be sure you’ve been supplied with good instructions for using and fitting your specific power supply.

All power supplies are different, so please check carefully the instructions supplied with your kit.

Part Details Quantity
+12V DC Power supply For a machine with a heated-bed, you usually need a 200W (or
higher-wattage) DC power supply running at +12V.
1
Power wiring loom A four-way ready-made power loom rated at 11A+ for connecting
to RAMPS.
1
Ferrules For termination of the power supply wires into the
screw-terminal inputs of RAMPS.
4
Fitting screws or tie-wraps The power supply is usually remotely mounted apart from the 3D
printer, but it’s a good idea to keep cables tidy by using
tie-wraps.
As required

If you need to connect up the wiring loom to your power supply, do that now. The general steps are as follows:

  1. Check the connections and power rating of your power supply.

    You should have two positive and two ground connections coming from your power supply, The connections from your power supply should be rated at 11A+ for the heated-bed connection and 5A+ for the motor and other components.

  2. Check the four RAMPS screw-terminal connections for power input.

    These connections are labeled: Two are positive and two are negative (GND). The screw terminal at the bottom-left corner of the RAMPS printed circuit board on the power input is a ground (GND) connection, this is usually a black wire from the power supply.

  3. Fit your GND wire into the appropriate screw-terminal.

    It’s always good practice to fit ferrules to the ends of any wires that will be inserted into a screw-terminal — before tightening.

  4. Connect the 5A+ supply for the motors and other parts of the RAMPS and Arduino board.

    If your power supply has cables of two different sizes, insert the thinner cable here.

  5. Connect the GND connection for the heated-bed.

  6. Connect the 11A+ connection for the heated-bed.

    Make sure this is screwed in nice and tight; this is the final connection, and it carries the most power used on the RAMPS board.

  7. Tidy up any wiring with tie-wraps as required.